Protective footwear, such as work boots and shoes, has been manufactured for many years. Such footwear usually has a protective steel toe cap and may be provided with either a spring steel arch support or shank and/or a stainless steel protective mid-sole which protects the arch, ball and toe regions of the foot from nails or other sharp objects which might penetrate the sole of the boot. In order to save sole material, which is relatively expensive, such footwear usually has a heel plug or filler which is positioned in the heel and reduces the amount of sole material in the heel portion.
Some problems associated with the manufacture of work footwear, as detailed hereinafter, relate to the material and composition of the heel plug, the strength of the shank and/or mid-sole, and the location of these parts in the sole area during boot production.
With respect to the heel plug the material thereof has in the past been a laminated paperboard or fiberboard material and the plugs have been die cut from large sheets of the laminated material. Due to lateral compression of the material during die cutting the composition tends to flake. The resulting flakes can migrate to the outer surfaces of the heel and arch area during production and can then require additional repair steps to remove blemishes caused thereby.
Shanks, usually produced from heat treated spring steel, are used to strengthen the arch area and thus must be accurately located to serve their intended purpose. Once the sole has set it is difficult, if not impossible, to detect any dislocation of a shank. Such dislocation results in factory rejects or wearer discomfort if not detected at the factory. One of many past attempts at rectifying this problem involved the clinching of the shank to the bottom of the insole. This results in damage to the metal last on which the footwear upper is attached.
Protective mid-soles are not without their problems as well. They are difficult to properly locate during production; they do not always provide complete coverage to the sole area of the boot; and they may not provide sufficient rigidity to a boot if a shank is not used in conjunction therewith. Some attempts have been made to use a steel shank in combination with the stainless steel mid-sole but, unless a layer of an appropriate material is placed between these metal components, unacceptable "squeaking" due to the components rubbing together can result. Furthermore, since the shank is harder than the mid-sole, repeated flexing of the sole during use can cause the shank to wear through the mid-sole and perhaps then through the sole of the boot or shoe.
It is important to realize that safety footwear is relatively expensive, resulting from the cost of the special components used therein and the care needed in manufacture. High standards must be maintained to provide the wearer with maximum comfort and protection. Experience has shown that a person wearing protective footwear tends to become careless as to where he places his foot while working as he relies on his footwear to protect him. If the footwear does not provide maximum protection the wearer is operating with a false sense of security.